1. Field of the Invention
The invention relates to a plotter stylus. A plotter stylus is a writing stylus for a plotter, that is to say for a machine for the automatic graphic representation of lines, symbols, diagrams or the like.
2. Description of the Prior Art
Hitherto ink pens, ball-point pens, particularly those with liquid inks, fiber-tip pens and felt-tip pens have been used as plotter styluses. Because plotters frequently operate at high writing speeds, it is scarcely possible to avoid failures with the known plotter styluses. Plotter styluses with the greatest possible writing lengths are also necessary in order to permit recordings to be made without interruption.
Known plotter styluses do not yet fulfill these conditions satisfactorily.
It is therefore the task of the invention to develop to a plotter stylus which permits high writing speeds, has a large ink volume, and also ensures as constant ink delivery independent of the ink supply with total utilization of the ink.
The achievement of this task starts with an ink writing implement, wherein the ink duct connecting the writing point to the ink supply space is surrounded by a pressure compensator. Such ink writing implements, which are described in detail in German Patent No. 2,609,668, for example, have been developed particularly for manual operation. The pressure compensator provided in these implements, also called a regulator, has the function of absorbing surplus ink in the case of variations in pressure, temperature or position, so that this ink does not emerge from the writing implement through the writing point.
In order to retain the ink in the pressure compensator of a manual implement under the various working and operating conditions, it is necessary for the chambers of the pressure compensation means to be dimensioned so that they retain the ink by virtue of their capillarity. However, this means that the fins demarcating the chambers must be arranged at very short mutual intervals, which are on the order of magnitude of 0.1 mm to 0.2 mm. In order to create a large volume for the pressure compensator in the smallest possible space, it is also essential for the fins to be dimensioned very thinly; their thickness is generally on the order of magnitude of 0.3 mm.
The production of pressure compensators with such fine lamellae is difficult and costly. Furthermore, the volume of these pressure compensators is too small for plotter styluses. Moreover, the capillarity of the pressure compensator has the disadvantageous effect that the quantity of the ink delivered via the writing point is a function of the volume of the ink still present in the supply space, and that a part of the ink is retained by capillary forces in the pressure compensator; therefore, the ink cannot be utilized totally.
A plotter stylus equipped with a pressure compensator which is free from these disadvantages is proposed according to the invention.